Optically Stimlated Luminescence Dating of Holocene Loess on the Chinese Loess Plateau and Its Implications for Evolution of East Asian Monsoon, Dust Activity, and Agriculture Civilization

Previous paleoclimate studies on loess deposits on the Chinese Loess Plateau (CLP) have primarily focused on tectonic, orbital, and millennial timescales prior to the Holocene, with chronological frameworks largely established through indirect approaches. Due to disturbances caused by human activities and a lack of reliable age constraints, Holocene paleoclimate reconstructions based on absolutely-dated chronology remain relatively scarce. In this study , we collected three high-resolution Holocene loess sections on the CLP. The closely-spaced quartz optically stimulated luminescence (OSL) dating method was used to establish corresponding section’s high-resolution chronology. And multiple climate proxies, including magnetic susceptibility, grain size, dust mass accumulation rate, and branched glycerol dialkyl glycerol tetraethers (brGDGTs), were employed to reconstruct paleoclimate. The following key findings were obtained: (1) For the first time, we reconstructed the late Holocene evolution of East Asian winter and summer monsoons on muti-centennial scales recorded in loess, and proposed that solar activity played a dominant role. By integrating records from three Holocene sections, we identifed a long-term trend monsoon shift around 6.5 ka, highlighting the dynamic control of ice volume and temperature at different stages. (2) Using synthesis approach from 23 loess sections, we obtained stacked Holocene dust mass accumulation rate variations across the CLP, which were determined by the variations of East Asian winter and summer monsoons. In addition, we identified asynchronous proximal and distal dust accumulation of Asia-sourced dust in the Northern Hemisphere during the Holocene, which probably modulated by both the monsoon and westerly circulation. (3) We found a soil cooling event of approximately 3 °C during ~7.5–6 ka on the CLP, which constrained the expansion of millet agriculture and cultural flourishing in northern China before 6 ka. In contrast, post-6 ka soil warming greatly promoted the development and expansion of millet agriculture, providing a critical economic foundation for human societal development. Our study provides robust evidences from loess for Holocene East Asian climate change and human civilization evolution, with significant implications for understanding future climate change.